The surface you're skipping on matters a lot...
I can do up to 200 skips without stopping and without the rope getting tangled in my building's laundry room (concrete floor). But when I tried in the park, I couldn't do more than 10-15 skips before the rope got tangled...
I have a "string" rope right now, which I don't really like - the plastic ones work better for me, for some reason.
Hmmm... another excuse for getting a mat?